Men jailed for violent sex assault and brutal death of Lynette Daley on remote beach

Two men who were found guilty over the death and violent sexual assault of Lynette Daley on a remote northern NSW beach in 2011 have been jailed.

Ms Daley, 33, died from injuries sustained in the violent sex act with her "'on-again-off-again" boyfriend Adrian Attwater, 43, and Paul Maris, 47, on a 2011 Australia Day camping trip to Ten Mile Beach, north of Iluka.

Adrian Attwater is due to be sentenced over the death and violent sexual assault of Lynette Daley. Photo: AAP

A jury in September this year found Attwater guilty of manslaughter and aggravated sexual assault, and Maris guilty of aggravated sexual assault and hindering the discovery of evidence.

At the NSW Supreme Court in Coffs Harbour on Friday, Attwater was sentenced to a minimum of 14 years, three months and a maximum of 19 years.

Maris was jailed for a minimum of six years, nine months and a maximum of nine years.

The five-week trial heard the trio had been drinking heavily and driving up and down the beach in Maris' troop carrier before Ms Daley was "repeatedly and vigorously" sexually assaulted on a mattress in the back of the vehicle.

Lynette Daley died on Ten Mile Beach in January 2011. Photo: Nine Network

The assault "substantially or significantly contributed to her death", he said.

The autopsy also revealed a small amount of methylamphetamine and a blood alcohol concentration of .303 - meaning she was "grossly intoxicated".

The prosecutor said Attwater told police "she was blind, she was off her f---ing face last night".

Attwater claimed Ms Daley had a fit or seizure in the ocean when she went for a swim while naked and he performed CPR after dragging her back to shore.

When questioned about how the trio came to have group sex, Attwater said: "These things happen ... girls will be girls, boys will be boys."

Both men told police they thought it was consensual.

Mr Strickland said Maris told police: "Well she didn't object when I jumped in the back, she'd moved over to give me oral."

Police initially charged Attwater and Maris over Ms Daley's death but, in 2012, the Office of the Director of Public Prosecutions decided not to proceed with the prosecution.

Last year, Director of Public Prosecutions Lloyd Babb, SC, took the rare step of asking an independent legal adviser to review the case, including whether Attwater and Maris should proceed to trial.

That review followed a Four Corners investigation in which the men were shown in police videos recorded at the time of Ms Daley's death describing events that took place in the back of the troop carrier.